[N3] Propertie values to one list property ???

Hello,

I would like to know how in n3 i can make a formula to get a list of 
values with all the values of a property.

For example i have :

:toto my:prop 1, 2, 3, 4.

and i would like to get :

:toto my:prop2 (1, 2, 3, 4).

Can anyone help me ??? Thanks.

BTW, with my innocence i would like to know wether we could add a

( :first :second :third | :rest )

construct in the N3 grammar to say

[ daml:first :first;
   daml:rest [
     daml:first :second;
     daml:rest [
       daml:first :third;
       daml:rest :rest
     ]
   ]
]

Thanks for your help all.
Didier Villevalois.